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// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_SNAPSHOT_CONTROLLER_H_
#define COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_SNAPSHOT_CONTROLLER_H_
#include "base/memory/raw_ptr.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/task/single_thread_task_runner.h"
namespace offline_pages {
// Takes various signals and produces StartSnapshot calls following a specific
// policy.
// Main invariants:
// - Some signals prevent more snapshots to be taken.
// OnLoad is currently such signal.
// - Once Reset() is called on the BackgroundSnapshotController, the delayed
// tasks are reset so no StartSnapshot calls is made 'cross-session'.
class BackgroundSnapshotController {
public:
enum class State {
READY, // Listening to input, will start snapshot when needed.
SNAPSHOT_PENDING, // Snapshot is in progress, don't start another.
STOPPED, // Terminal state, no snapshots until reset.
};
// The expected quality of a page based on its current loading progress.
enum class PageQuality {
// Not loaded enough to reach a minimum level of quality. Snapshots taken at
// this point are expected to be useless.
POOR = 0,
// A minimal level of quality has been attained but the page is still
// loading so its quality is continuously increasing. One or more snapshots
// could be taken at this stage as later ones are expected to have higher
// quality.
FAIR_AND_IMPROVING,
// The page is loaded enough and has attained its peak expected quality.
// Snapshots taken at this point are not expected to increase in quality
// after the first one.
HIGH,
};
// Client of the BackgroundSnapshotController.
class Client {
public:
// Invoked at a good moment to start a snapshot.
virtual void StartSnapshot() = 0;
protected:
virtual ~Client() {}
};
BackgroundSnapshotController(
const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
BackgroundSnapshotController::Client* client,
bool renovations_enabled);
BackgroundSnapshotController(const BackgroundSnapshotController&) = delete;
BackgroundSnapshotController& operator=(const BackgroundSnapshotController&) =
delete;
virtual ~BackgroundSnapshotController();
// Resets the 'session', returning controller to initial state.
void Reset();
// Stops current session, no more Client::StartSnapshot calls will be
// invoked from the BackgroundSnapshotController until current session is
// Reset(). Called by Client, for example when it encounters an error loading
// the page.
void Stop();
// The Client calls this when renovations have completed.
void RenovationsCompleted();
// Invoked from WebContentObserver::DocumentOnLoadCompletedInPrimaryMainFrame
void DocumentOnLoadCompletedInPrimaryMainFrame();
int64_t GetDelayAfterDocumentOnLoadCompletedForTest();
int64_t GetDelayAfterRenovationsCompletedForTest();
private:
void MaybeStartSnapshot();
void MaybeStartSnapshotThenStop();
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
// Client owns this class.
raw_ptr<BackgroundSnapshotController::Client> client_;
BackgroundSnapshotController::State state_;
int64_t delay_after_document_on_load_completed_ms_;
int64_t delay_after_renovations_completed_ms_;
base::WeakPtrFactory<BackgroundSnapshotController> weak_ptr_factory_{this};
};
} // namespace offline_pages
#endif // COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_SNAPSHOT_CONTROLLER_H_
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